The Egyptian stock exchange briefly halted dealing in OCI's shares, before resuming trading after it received a statement from the company.

In that statement, OCI said talks with the tax authority were ongoing and it hoped to reveal details at the earliest opportunity.

The Egyptian authorities have been investigating claims the company failed to pay some 14 billion Egyptian pounds of taxes on the sale of Orascom Building, an OCI subsidiary, to French firm Lafarge, according to state media.

Earlier this month the firm's chief executive officer, Nassef Sawiris, and his father were barred from leaving the country as part of an investigation into tax evasion.

OCI is separately finalising a deal that might lead it to leave the Egyptian stock market, against the government's wishes.

Dutch-listed parent company OCI NV announced an acquisition deal in January under which holders of OCI's GDRs (global depositary receipts) were offered shares in OCI NV, while holders of the firm's Egypt-listed ordinary shares got the option of cash or OCI NV shares.

OCI's board approved the deal in February, but Egypt's financial regulator has delayed its completion, requesting more information.-Reuters